CHAPTER 1

HONORS

BIOLOGY

I. BIOLOGY

• Study of life and how living organisms interact with their environment

• Because encompasses so much, scientists have created hierarchy of organization

Hierarchy of organization• Biosphere • Ecosystem • Community • Population• Organism• Organ System• Organs • Tissues • Cell• Organelle• Molecules• Atoms

Biosphere

Ecosystem

Community

Population

Organism

Organ systems

Organs

Tissues

Cells

organelles Atoms/

molecules

II. Living Organisms & their Environment

• Interactions of organisms with environment make up a web or relationship within ecosystem

– Ex. Producers, consumers, decomposers

• Success of ecosystem depends on:

1. Recycling of chemical nutrients - nonliving, required for life2. Recycling of chemical nrg - enters as light exits as heat

Cyclingofchemicalnutrients

Producers(such as plants)

Chemical energy

Consumers(such as animals

Heat

Heat

III. Cells - Basic Unit of Life

• Cells are the basic unit of life because

– Make up all living organisms– Smallest structure that can perform all

activities needed to live

Types of Cells

1. Prokaryoticpro-

karyote -

anucleated

No membranous organelles

2.EukaryoticEu -Karyotic -Nucleated, more complex, larger

IV. Unity of Life• All living organisms have common

denominator --- DNA• Structure

– Double helix– 5 carbon sugar– Phosphate– Nitrogen base (A,T,C,G)

• Function - – Instructions for cells activities– Blueprint of life – Order of bases are important

Nucleotide

Single strand of DNA

V. Characteristics of Life• 7 Characterics all living things share

– Heirarchy / Order– Homeostasis / Regulation– Growth/development– Metabolism / nrg processing– Respond to env.– Reproduce– Evolve

VI. Diversity of Life• Diversity results from the difference in the

structure of DNA (order of bases)• Approx 1.8 million known species• Scientists believe 10 - 200 million exist• To organize and classify all these

organisms scientists use TAXONOMY (name and classify organisms)

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Heirarchy of Organization• D• K• P• C• O• F• G• S

3 Domains/ 6 kingdoms

– Bacteria - prok.simple, most unicellular• Includes eubcteria kingdom

– Archae - prok., simple, most unicellular, live in harsh conditions

• Includes archaebacteria kingdom

– Eukarya - euk. • Includes protists, animalia, plant, fungus kingdoms

All these domains are interconnected through web of life

bacteria

archaebacteria

eukarya

VII. Evolution

Evolution occurs as a result of diversity

Evolution- change in a population over time

CHARLES DARWINFather of evolution -

Published a book

“On Origin of Species b Means of Natural Selection”

2 main points of theory of evolution:

1. Descent with Modification:

all living species descended from a common ancestor, but changed over time(descent with modification to adopt to environment.

2. Natural Selection

2 concepts of natural selection

1. Individuals within a population have variety which allows them to survive in the environment

2. Overproduction and competition - population produce more offspring then will survive, with more individuals in env. competition occurs (natural selection)

D

A

R

W

I

N

Natural

Selection

VIII. How Do Scientists Learn?

• Science - “to know”

• 2 approaches to study science1. Discovery Based Science

2. Hypothesis based Science

A. Discovery Based Science

• Describes nature• Uses observations and measurements• Describes natural phenomenon• Based on INDUCTIVE reasoning

(observations)

• Ex. Because can see cells under a microscope in all living organisms, conclude that all living organisms are made of cells

B. Hypothesis Based Science

• Propose and test a hypothesis• Leads to prediction to be tested (if then

statements)• Based on Deductive Reasoning

(general to specific)

Ex. IF all organisms are made of cells THEN humans are made of cells

Steps to hypothesis based science

• Scientific Method - sequence of steps to solve a scientific problem

• 6 basic steps• Used by all scientists to create a

standard to communicate results.Sharing Information• Publication• Peer reviewed publication

Types of Experiments

• Blind study- patient does not know if getting medicine or not – Eliminates bias on patient part

• Double Blind - – Patient and scientists does not know if

getting the real medicine or placebo– Eliminates bias on both sides

Steps of Scientific Method• P

• I

• H

• E

• D

• C

Laws and Theories• Theory - hypothesis tested over long

time. Can be modified– Ex. Theory of evolution …….

• Law - Theory tested over long period of time.– Newton’s laws……

XI. Bio Connected to our Lives

• It explains – relationship b/t all living organisms– Diversity of organisms– How the env. Affects organisms and their

change– How science and technology are

interdependent

Science and tech. interdep.

– How science and technology are interdependent

ex. • Food - genetically modified• Air and water pollution• Cloning/stem cell• Nutritional supplements• Medical technology• Genetic engineering (vaccines, cures, etc…)• medicine to help us live longer and healthier• Living longer and healthier - good or bad?